What makes this a bit hard for some of the members reading and responding is that there is a very different attitude towards life, death, and the connection of all in the universe to a serious Buddhist.
It goes way beyond being a vegetarian/vegan. There is a life force in everything. His wife may seem a bit off to some of us, but from here point of view we are the ones who are crazy.
They are going to have to work this out together. Hopefully, some family counseling will make a compromise possible.
My wife of 24 years does not like guns, especially handguns, so I stopped working on guns. It wasn't an order from her, but I know how she feels and respect it. Not a big thing on my end, but important to her. When I get the new shop done, I will probably go back to building black powder rifles, which she is OK with.
I like making knives and building things. She happily allows my boxes of stuff to sit in many places around the house. The garage, yard, two of the upstairs bedrooms are mine to do with as I wish. The downstairs is decorated with my antique phones, swords sitting in the corners, bear rug on the floor, Menachem Boas paintings, and other antique stuff ... along with some of her pretty things. She has grown to actually like this. The old farm stuff, building supplies, tents and tables, etc. is OK with her as long as I keep it sort of neat (anyone who has been at my place knows that there are formal decks and tidy areas for socializing ... and areas that are out of junk-wars).
She is 100% behind us building the big new shop in the second lot and plans on spending time out there with me when it is done. Maybe she will just read, maybe she will put labels on knives and stuff being shipped, maybe she will paint little doo-dads ... but her support of the new shop makes it a good deal. All she wants is a comfy chair, an air conditioned clean shop, and to hang around while I work. I had a pretty shop apron made for her last Christmas that says "Shop Lamb". We plan on growing old out there together.